|Title of Project|
|Investigation of the effectiveness of fungicides for control of phoma stem canker pathogens of oilseed rape|
|This project going to be…|
|Full Name of Supervisor|
|Dr Chinthani Karandeni Dewage|
|Institution Department and Address|
Hatfield, Hertfordshire AL10 9AB
|Full name of the day to day supervisor and/or arrangements for supervision|
|Dr Chinthani Karandeni Dewage|
|Date of Project Commencement|
|Brief Description of Project|
|Background: Phoma stem canker (PSC) is a major disease problem on oilseed rape (Brassica napus) in the UK, causing losses worth more than £80M p.a. The disease is caused by two closely related species, Leptosphaeria maculans (Lm) and L. biglobosa (Lb), which co-exist on their host. Lm is generally considered more damaging than Lb, because Lm is often associated with damaging stem base cankers and Lb is often associated with less damaging upper stem lesions. However, studies show that Lb can also cause substantial yield losses in areas where Lb is present as the predominant pathogen. Although, both Lm and Lb are present in UK, there has been little work on Lb with no control strategies targeted on Lb. There have been previous studies reporting that Lb is less sensitive to some azole fungicides that are commonly used for the control of phoma stem canker (Eckert et al. 2010; Huang et al. 2011). Investigation of fungicide-sensitivity in other fungal pathogens showed that mutations in the sterol 14α-demethylase (CYP51) gene is the main cause of development of fungicide insensitivity/resistance against azole fungicides (Cools & Fraaije, 2008; Carter et al., 2014). Although differences in sensitivity to flusilazole amongst Lm isolates have been observed, no mutations were detected in the Lm CYP51 gene (Huang et al., 2011). There have been no major structural differences identified between the predicted Lm and Lm CYP51 protein models (Sewell et al. 2017). Therefore, this project aims to investigate the invitro and in planta CYP51 gene expression differences between Lm and Lb as a contributing factor for the fungicide insensitivity.
Methodology: Student will be provided with RNA samples extracted from cotyledons of B. napus inoculated with L. maculans or L. biglobosa. The sampling has been done at two different time points (3 and 12 days after inoculation). The work involves cDNA synthesis and RT PCR with specific primers to detect the in planta CYP51 gene expression of these two pathogens. Mycelia samples have also been collected from invitro culture of the two pathogens. These samples will be used to investigate the invitro CYP51 gene expression from L. maculans and L. biglobosa. Comparison of gene expression between the two pathogens both in planta and in vitro can be used to improve our knowledge about the differences between these two pathogens in their insensitivity to azole fungicides.
This project will enable the student to understand key principles of plant pathology and to gain skills in molecular biology techniques including, RNA extraction, PCR, gene-expression analysis, etc. The student will work as part of a research group interacting with other PhD, MSc research students working on various aspects of plant pathology (host resistance, pathogen population studies, inter-species interactions, etc.), that will be beneficial for the students development.
|Attach the recommended reading for the project|
|Eckert, M. R., Rossall, S., Selley, A. & Fitt, B. D. L. Effects of fungicides on in vitro spore germination and mycelial growth of the phytopathogens Leptosphaeria maculans and L. biglobosa (Phoma stem canker of oilseed rape). Pest Manag. Sci. 66, 396–405 (2010).
Huang, Y. J. et al. Effects of fungicide on growth of Leptosphaeria maculans and L. biglobosa in relation to development of phoma stem canker on oilseed rape (Brassica napus). Plant Pathol. 60, 607–620 (2011).
Carter, H. E. et al. Alterations in the predicted regulatory and coding regions of the sterol 14α-demethylase gene (CYP51) confer decreased azole sensitivity in the oilseed rape pathogen Pyrenopeziza brassicae. Mol. Plant Pathol. 15, 513–522 (2014).
Sewell, Thomas R., et al. “Azole sensitivity in Leptosphaeria pathogens of oilseed rape: the role of lanosterol 14α-demethylase.” Scientific Reports 7.1 (2017): 1-12.